A crane at a junkyard lifts a car with a mass of 1800 kg at a constant speed to a height of 16 m. It then turns and drops the car into a car crusher on the ground below. a) Determine the maximum gravitational potential energy of the car b) Determine the speed of the car when it has fallen 12 m

When a 12 kg object increases its potential energy by 720 J, approximately how has its position changed?  a) It has risen vertically 60m b) It has fallen vertically 6m  c) It has risen vertically 6m d) It has fallen vertically 60m

Two balls having different masses reach the same height when shot into the air from the ground. If there is no air drag, which of the following statements must be true? (More than one statement may be true.) A. Both balls left the ground with the same speed. B. Both balls left the ground with the same kinetic energy. C. Both balls will have the same gravitational potential energy at the highest point. D. The heavier ball must have left the ground with a greater speed than the lighter ball. E. Both balls have no acceleration at their highest point.

C7 9.) If the orbit is elliptical, rather than circular, what can be said about the work done by the Sun on Earth? a.) It does not matter whether the orbit is circular or elliptical, no work is done. b.) The work the Sun does on Earth causes the tides.    c.) Whether the orbit is circular or elliptical, work must be done to propel Earth around the Sun. d.) If the orbit is elliptical, work is done to speed up or to slow down Earth, depending on its location in orbit. e.) The work the Sun does on Earth accounts for Earth's changes of season.

An object with a mass of 15kg slides down an incline with a length of 6.0m at an angle of 28 degrees from horizontal.  The coefficient of friction between the object and incline is 0.25  a) How much work does the gravitational force perform on the object? b) How much work does the frictional force perform on the object?  c) What will its speed be as it reaches the bottom of the incline?

3.) A public bus (with mass 2500 kg) is traveling along H1 highway at a speed of 3 m/s. Suddenly the bus- driver jams on the brakes and the bus comes to a complete stop. a) How much kinetic energy does the bus have initially? b) How much kinetic energy does the bus have when it comes to a complete stop? c) If the brakes exert a force of 1000 N, how much braking distance does the car need to come to a complete stop? d) If the car was traveling at double the speed (6 m/s), how much braking distance would be required?

An athlete throws a 1.5 kg ball with a horizontal speed of 9 m/s, from a height of 4.8 metres above the ground.  a) Calculate the kinetic energy, gravitational potential energy and total mechanical energy of the ball at its starting position. b) Calculate the maximum speed attained by the ball, just as it reaches the ground's surface.